com.vaadin.flow.data.provider

Class InMemoryDataProviderHelpers

java.lang.Object

com.vaadin.flow.data.provider.InMemoryDataProviderHelpers

public class InMemoryDataProviderHelpers
extends Object

Helper methods for implementing InMemoryDataProviders.

This class is intended primarily for internal use.

Since:

1.0

Author:

Vaadin Ltd

Field Summary

Fields

Modifier and Type	Field and Description
static SerializableSupplier<Locale>	CURRENT_LOCALE_SUPPLIER Supplier that attempts to resolve a locale from the current UI.

Method Summary

Modifier and Type	Method and Description
static <T,V> SerializablePredicate<T>	createEqualsFilter(ValueProvider<T,V> valueProvider, V requiredValue) Creates a predicate that compares equality of the given required value to the value the given value provider obtains.
static <T,V> SerializablePredicate<T>	createValueProviderFilter(ValueProvider<T,V> valueProvider, SerializablePredicate<V> valueFilter) Creates a new predicate from the given predicate and value provider.
static <T> DataProvider<T,String>	filteringByCaseInsensitiveString(InMemoryDataProvider<T> dataProvider, ValueProvider<T,String> valueProvider, SerializableBiPredicate<String,String> predicate, SerializableSupplier<Locale> localeSupplier) Wraps a given data provider so that its filter tests the given predicate with the lower case string provided by the given value provider.
static <T,V,Q> DataProvider<T,Q>	filteringByIgnoreNull(InMemoryDataProvider<T> dataProvider, ValueProvider<T,V> valueProvider, SerializableBiPredicate<V,Q> predicate) Wraps a given data provider so that its filter ignores null items returned by the given value provider.
static <V extends Comparable<? super V>> Comparator<V>	getNaturalSortComparator(SortDirection sortDirection) Gets the natural order comparator for the type argument, or the natural order comparator reversed if the given sorting direction is SortDirection.DESCENDING.
static <V extends Comparable<? super V>,T> SerializableComparator<T>	propertyComparator(ValueProvider<T,V> valueProvider, SortDirection sortDirection) Creates a comparator for the return type of the given ValueProvider, sorted in the direction specified by the given SortDirection.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CURRENT_LOCALE_SUPPLIER

public static final SerializableSupplier<Locale> CURRENT_LOCALE_SUPPLIER

Supplier that attempts to resolve a locale from the current UI. Returns the system's default locale as a fallback.

Method Detail

filteringByIgnoreNull

public static <T,V,Q> DataProvider<T,Q> filteringByIgnoreNull(InMemoryDataProvider<T> dataProvider,
                                                              ValueProvider<T,V> valueProvider,
                                                              SerializableBiPredicate<V,Q> predicate)

Wraps a given data provider so that its filter ignores null items returned by the given value provider.

Type Parameters:

T - the provided data type

Q - the filter type

V - the data provider object type

Parameters:

dataProvider - the data provider to wrap

valueProvider - the value provider for providing values to filter

predicate - the predicate to combine null filtering with

Returns:

the wrapped data provider

filteringByCaseInsensitiveString

public static <T> DataProvider<T,String> filteringByCaseInsensitiveString(InMemoryDataProvider<T> dataProvider,
                                                                          ValueProvider<T,String> valueProvider,
                                                                          SerializableBiPredicate<String,String> predicate,
                                                                          SerializableSupplier<Locale> localeSupplier)

Wraps a given data provider so that its filter tests the given predicate with the lower case string provided by the given value provider.

Type Parameters:

T - the data provider object type

Parameters:

dataProvider - the data provider to wrap

valueProvider - the value provider for providing string values to filter

predicate - the predicate to use for comparing the resulting lower case strings

localeSupplier - the locale to use when converting strings to lower case

Returns:

the wrapped data provider

propertyComparator

public static <V extends Comparable<? super V>,T> SerializableComparator<T> propertyComparator(ValueProvider<T,V> valueProvider,
                                                                                               SortDirection sortDirection)

Creates a comparator for the return type of the given ValueProvider, sorted in the direction specified by the given SortDirection.

Type Parameters:

T - the data provider object type

V - the provided value type

Parameters:

valueProvider - the value provider to use

sortDirection - the sort direction to use

Returns:

the created comparator

getNaturalSortComparator

public static <V extends Comparable<? super V>> Comparator<V> getNaturalSortComparator(SortDirection sortDirection)

Gets the natural order comparator for the type argument, or the natural order comparator reversed if the given sorting direction is SortDirection.DESCENDING.

Type Parameters:

V - the objects to compare

Parameters:

sortDirection - the sort direction to use

Returns:

the natural comparator, with ordering defined by the given sort direction

createValueProviderFilter

public static <T,V> SerializablePredicate<T> createValueProviderFilter(ValueProvider<T,V> valueProvider,
                                                                       SerializablePredicate<V> valueFilter)

Creates a new predicate from the given predicate and value provider. This allows using a predicate of the value providers return type with objects of the value providers type.

Type Parameters:

T - the data provider object type

V - the provided value type

Parameters:

valueProvider - the value provider to use

valueFilter - the original predicate

Returns:

the created predicate

createEqualsFilter

public static <T,V> SerializablePredicate<T> createEqualsFilter(ValueProvider<T,V> valueProvider,
                                                                V requiredValue)

Creates a predicate that compares equality of the given required value to the value the given value provider obtains.

Type Parameters:

T - the data provider object type

V - the provided value type

Parameters:

valueProvider - the value provider to use

requiredValue - the required value

Returns:

the created predicate